Oceans cover more than 70% of the earths surface and hold more than 20,000 species of fish, of these some 370 species are sharks. Long before dinosaurs existed, sharks roamed the waters. They first originated more than 400 million years ago and have changed very little in the last 100 million years. Today, few other species on earth inspire so much respect and fear. These amazing predators sit atop the marine food chain. By weeding out the week and injured they help maintain a balanced ecosystem.

Sharks are highly tuned hunting machines that rely on their specialized senses to catch prey. Using their sharp sense of hearing they can detect sound vibrations up to 3,000 feet away. They are especially sensitive to the low frequency pulses from struggling prey. As a shark gets closer to the catch, its sense of smell takes over. It can detect a single drop of blood in 25 gallons of water. Water flows through nostrils on the underside of its snout, which gives the shark a steady stream of olfactory information. Near the snout, sharks also have tiny jelly filled pores, which pick up electrical signals created by moving animals. This is like an extra sense that helps sharks find prey, even if it’s hiding under the sand.

When we think of sharks, we can’t help but think of their teeth. Sharks use and lose their teeth all of the time. Some species shed as many as 30,000 during their lifetime, but replacements are always nearby. But rows of teeth make it possible to rotate in new teeth when needed. Besides their reputation, one thing that distinguishes sharks from other fish is their skeleton, which is made of tough, flexible cartilage instead of bone. Cartilage is lighter than bone, so the shark uses less energy as it swims, than a bony fish does. Tough skin covers its streamlined body, tiny teeth- like structures make the skin as rough as sand paper, making the skin as rough as sand paper and protect the shark from injury. These teeth point backward to reduce the drag from the water, as the shark races through it. So many advantages make sharks one of the most efficient predators on earth!